The American Cancer Society estimates that in 2004 there were more than 350,000 new cases of breast or colorectal cancers and almost 100,000 deaths related to these cancers. This is a substantial public health problem that remains the focus the National Surgical Adjuvant Breast and Bowel Project (NSABP). For more than 40 years, the NSABP has successfully conducted large-scale, randomized clinical trials in breast and colorectal cancer designed to improve the standard of care, quality of life and survival of persons who develop these diseases. This research proposal requests funding to enable the continued functioning of the Biostatistical Center of the NSABP which provides: 1) data management support for the collection and processing of data from NSABP trials; 2) quality assurance programs which ensure that the collected data is of the highest integrity; 3) scientific collaboration in the development of the NSABP research agenda and logistical support for the conduct of the research; and 4) statistical leadership and support for the design, monitoring and analysis of trials and correlative studies. In 2002-2003, the NSABP accounted for 64% of the breast cancer patients and 78% of the colorectal cancer patients who entered the NCI Phase III trials that were available for these patients. Other significant accomplishments made in support of the NSABP scientific agenda during the full course of the prior funding period include: 1) opening of accrual for nine new protocols with 21,000 newly-enrolled patients; 2) data collection and management for 43,000 patients; 3) conducting over 380 site visit audits involving the review of over 5,200 patients charts; 4) implementation of web-based data collection procedures; 5) initiation of an ongoing effort to analyze microarray data to assess prognostic and predictive gene profiles; and 6) the publication of almost 200 manuscripts, 36 of which deal with methodology. In the proposed project period, funding will be used to sustain our efforts as a data and statistical center in support of the NSABP scientific agenda and to enhance the utilization of newer technologies for data collection, data management and the communication and training of clinical site collaborators with the goal of developing more efficient methodologies to design, conduct and analyze clinical trials.